Cartridge case



Feb. 23, 1965 w. 1'. JOHNSON ETAL CARTRIDGE CASE Filed Sept. 11, 1962 f'-\- \-u l9 I? H l4 INVENTORS.

WALTER T. JOHNSON STANLEY P. PROSEN ATTY.

AGENT United States Patent Ofiice 3,i?0,4hl Patented Feb. 23, 1965 3,170,401 CARTRIDGE CASE Walter T. Johnson, Kensington, and Stanley P. Prosen,

Lanham, Md., assignors to theUnited States of America as represented by the Secretary of the Navy Filed Sept. 11, 1962, Ser. No. 222,979 6 Claims. (Cl. 102-43) (Granted under Title 35, U.S. Code (1952), sec. 266) constructed of metal which have to be discarded after one firing or be resized for use again. Cartridge cases in recent years have utilized combustible side walls with a metallic base and partial side wall, however, before reuse they generally have to be resized and a second problem has occurred in the prevention of the'escapement of the gases upon ignition of the explosive material within the cartridge. Although the prior art devices work Well for. their intended purpose, they have not been entirely satisfactory in that resizing is still required and the blow-by of the exploding gases has been harmful to the gun.

The general purpose of the present invention is to provide a cartridge case which embraces all the advantages of similarly employed prior art devices and possesses none of the aforedescribed disadvantages. To'attain this, the present invention utilizes a rigid base which is not deformed by the explosion of the combustible material within the case upon firing the gun and which as a result is reusable many times without resizing between uses. Attached to this rigid base is a plastic obturator which is flexible and effectively seals the cartridge case to the bore of the gun upon firing and which also is reusable many times with no intermediate preparatory steps re quired to enable it to be'used for a refiring. I Attached to this plastic obturator is a container containing an explosive material which propels missiles from the gun.

An object of the present invention is'to provide a cartridge case whichis sufiiciently strong to withstand the high pressure of an explosion without distortion and which effectively prevents the escapement of the explosive gases out of the breech end of the gun upon firing.

Another object of the present invention is to provide a cartridge case which is reuseable without resizing or other alteration to the used parts and requires only the replacement of the spent explosive material.

A further object of the present invention is to provide a cartridge case which is lighter in weight by utilizing a smaller amount of metal in production of the cartridge while maintaining the requirement of suflicient strength to withstand the explosion.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes understood by reference to the following detailed description when considered in connection with the accompanying drawing.

The figure of the present invention is an illustrative embodiment, partially in section, of the present invention.

Referring to the drawing the base 6 is shown with the extractor ring 7 forming an integral part of the base and having a hole 8 through the center of the circular base to provide for the insertion of a suitable primer to ignite explosive material within the case. The base is constructed of a rigid material being of suitable strength to withstand explosive pressure produced by igniting the explosive material within the case upon firing a missile from the gun. Some material which has been found to be able to withstand the pressure without becoming deformed either due to the heat or the pressure are metals such as aluminum, brass, magnesium or steel and a plastic material which has been reinforced with glass fibers or a polycarbonate plastic. The bottom'portion of the base 6 is generally flat and the cylindrical side wall 11 extends upward from the base or flat portion no greater than one-fourth the diameter of the base 6 or no more than one-twelfth the total length of the entire cartridge case. The upper portion of the base 6 forms a gradually increasing nonuniform conical section side wall 12 with respect to the vertical cylindrical side wall 11 as viewed in the drawing and terminates in an annular groove 9. On the upper portion of the base at the center there is a cylindrical protrusion 13 which'surrounds the portion of the primer 8.

Attached to the base 6 is a plastic obturator 14 which is held in place by engaging groove 9 and also by being retained by the retaining washer 16. Retaining washer 16 may take the form as shown in that it fits in a slot of the protrusion 13 or may be any suitable retaining washer having compressible clogs to maintain the retaining washer 15 in place on protrusion 13. The plastic obturator 14 conforms in shape to the upper portion of the base 6 and terminates at the side in a cylindrical side wall 17 which is the same dimension as the cylindrical wall 11 on the base 6. The cylindrical side wall 17 of the obturator 14 etxends the side wall no more than one-half the diameter of the base 6 orno more than one sixth total length of the cartridge case. The upper portion of the obturator 14 conforms generally to the shape of the lower portion of the obturator with the exception of the retaining groove 18 which is formed or molded with the obturator to maintain the combustible side wall of the cartridge in place. The plastic obturator14 is constructed of relatively flexible plastic material such as high density polyethylene or linear polyethylene or polypropylene or a polycarbonate or of a flexible acrylonitrile-butadiene-styrene (ABS) polymer.

Proceeding upwards on the drawing the side wall 19 is attached to the plastic obturator 14 and held in place by means of a retaining groove 18. The side wall 19 can be of a combustible nitrocellulose construction or it may be a plastic side wall or it could even be formed of a thin metallic material. The side wall as shown has a uniform thickness throughout, however, it may also be tapered toward the upper portion so that it is thinner at the top than at the base. If an explosive material has a sufficient consistency to maintain its own shape there need be no side Wall 19 whatsoever. The function of the combustible side wall 19 is to provide the container which will contain the explosive material placed within the internal portion of the side Walls since, generally speaking, the explosive material is not able to withstand severe shocks or jars without cracking or crumbling. In utilizing a combustible side wall a suitable method of attaching the side Wall to the obturator 14 has been found to be either heating the combustible material and making it soft and pliable or immersing the end of the side wall into a solvent to make it soft and pliable and pressing the side wall into the plastic obturator so that it forms and hardens within the retaining groove 18. The side wall 19 continues the cylindrical side wall 11 of the base being of the same diameter and is generally at least three quarters of the total length of the cartridge case or at least two times the daimeter of the base 6.

In operation after the cartridge case has been assembled and filled with an explosive material and projectile (not sown) and placed within the breech of the gun, the breech is closed and the explosive is ignited through the primer. The expanding gases project the missile out of 3 the muzzle of the gun while the plastic obturator 14, being flexible, forms a gas-tight seal to prevent the escape- ,ment of the gases between the cartridge case and the bore of the gun while the rigid base 6 supports the plastic obturator 14. In the firing of a shell the combustible side wall 19 is consumed (if made of a cornbustile material) and to reuse the base 6 and the plastic obturator 14 it is only necessary to attach it to a container and fill it with an explosive and a projectile.

The present invention contains a new and novel result in that the base 6 is reuseable without resizing and the plastic obturator 14 forms an effective seal to prevent the exploding gases to escape the breech of the gun there by eliminating both reduction in the effective propelling power of the missile as well as eliminating damage to the gun due to the escapement of the hot corrosive gases. Plastic obturator 14 being formed of a flexible material is not stressed beyond its elastic limit and as a result does not require resizing or other mechanical processing to readapt it to be reused in a subsequent cartridge case. By the use of a combustible side wall the only portions remaining to the cartridge case after firing are the base 6 and plastic obturator 14 which result in a smaller volume of material to be returned or destroyed. By utilizing a smaller base than normally used heretofore it is possible to reduce both the weight and the use of valuable metal within the cartridge case.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A cartridge case for use in a gun having a bore comprising, in combination; a circular base having a generally flat portion, an extractor ring extending laterally from the flat portion, a primer for igniting an explosive disposed in the generally flat portion, and an outside cylindrical side wall extending longitudinally from the junction of the fiat portion and the extractor ring less than one-fourth the diameter of the circular base; a plastic obturator, separate and distinct from said circular base, attached to said circular base and having an outside cylindrical side wall extending longitudinally from the side wall of the circular base less than one-half the diameter of the circular base, the diameter of the side Wall of the obturator being of the same diameter as the side wall of the circular base; and a container for explosive material, separate and distinct from said circular base and said obturator, attached to said obturator and having an outside cylindrical side wall extending longitudinally at least twice the diameter of the circular base, the diameter of the container being of the same diameter as the side wall of the circular base; the outside cylindrical wall of the obturator being in contact with the cylindrical side wall of the circular base and the cylindrical side wall of the container to form a uniform outside cylindrical surface for the entire cartridge case, whereby upon ignition Within a gun of the explosive material within the container, the base supports the obturator and the obturator forms a gas-tight seal between the cartridge and gun bore as a missile is projected from the gun.

2. A cartridge case as recited in claim 1 wherein the container for explosive material is composed of completely combustible material.

3. A cartridge case for use in propelling a projectile from a gun comprising in combination; a rigid base having a generally flat portion, a hollow cylindrical protrusion in the center of the fiat portion, a primer disposed in said protrusion, a comically-shaped side wall of uniform outside diameter extending longitudinally from the flat portion; a flexible plastic obturator, separate and distinct from said rigid base, attached to said rigid base and having a side wall of the same uni-form outside diameter as the side wall of the rigid base, the side wall of the obturator contacting and continuing from the side wall of the base; and a container for holding an explosive propellant, separate and distinct from said rigid base and said plastic obturator, attached to said plastic obturator and having a side Wall of the same uniform outside diameter as the side wall of the rigid base and contacting and continuing from the side wall of the obturator; whereby the outside diameter of the base, obturator and container form a successive and uniform outside cylindrical configuration for the cartridge case.

4. A cartridge case as recited in claim 3 wherein the container is composed of completely combustible mate rial and the base is metallic.

5. A cartridge case as recited in claim 4- wherein the plastic obturator is attached to the base by means of a retainer ring on the cylindrical protrusion of the base.

6. A cartridge case as recited in claim 5 wherein the plastic obturator has an annular groove molded therein for attaching and centering the container thereto.

References Cited by the Examiner UNITED STATES PATENTS 193,658 7/77 Hotchkiss 102-44 226,117 3/80 Saget 102-44 1,605,655 11/26 Du Pont 102-42 2,818,021 12/57 Boehm et a1 102-44 2,982,211 5/61 Beal et al. 102-43 3,026,802 3/62 Barnet et a1 102-44 X 3,026,803 3/63 Metzger 102-43 FOREIGN PATENTS 487,320 11/37 Great Britain.

SAMUEL FEINBERG, Primary Examiner.

SAMUEL BOYD, Examiner. 

1. A CARTRIDGE CASE FOR USE IN A GUN HAVING A BORE COMPRISING, IN COMBINATION; A CIRCULAR BASE HAVING A GENERALLY FLAT PORTION, AN EXTRACTOR RING EXTENDING LATERALLY FROM THE FLAT PORTION, A PRIMER FOR IGNITING AN EXPLOSIVE DISPOSED IN THE GENERALLY FLAT PORTION, AND AN OUTSIDE CYLINDRICAL SIDE WALL EXTENDING LONGITUDINALLY FROM THE JUNCTION OF THE FLAT PORTION AND THE EXTRACTOR RING LESS THAN ONE-FOURTH THE DIAMETER OF THE CIRCULAR BASE; A PLASTIC ABTURATOR, SEPARATE AND DISTINCT FROM SAID CIRCULAR BASE, ATTACHED TO SAID CIRCULAR BASE AND HAVING AN OUTSIDE CYLINDRICAL SIDE WALL EXTENDING LONGITUDINALLY FROM THE SIDE WALL OF THE CIRCULAR BASE LESS THAN ONE-HALF THE DIAMETER OF THE CIRCULAR BASE, THE DIAMETER OF THE SIDE WALL OF THE OBTURATOR BEING OF THE SAME DIAMETER AS THE SIDE WALL OF THE CIRCULAR BASE; AND A CONTAINER FOR EXPLOSIVE MATERIAL, SEPARATE AND DISTINCT FROM SAID CIRCULAR BASE AND SAID OBTURATOR, ATTACHED TO SAID OBTURATOR AND HAVING AN OUTSIDE CYLINDRICAL SIDE WALL EXTENDING LONGITUDINALLY AT LEAST TWICE THE DIAMETER OF THE CIRCULAR BASE, THE DIAMETER OF THE CONTAINER BEING OF THE SAME DIAMETER AS THE SIDE WALL OF THE CIRCULAR BASE; THE OUTSIDE CYLINDRICAL WALL OF THE OBTURATOR BEING IN CONTACT WITH THE CYLINDRICAL SIDE WALL OF THE CIRCULAR BASE AND THE CYLINDRICAL SIDE WALL OF THE CONTAINER TO FORM A UNIFORM OUTSIDE CYLINDRICAL SURFACE FOR THE ENTIRE CARTRIDGE CASE, WHEREBY UPON IGNITION WITHIN A GUN OF THE EXPLOSIVE MATERIAL WITHIN THE CONTAINER, THE BASE SUPPORTS THE OBTURATOR AND THE OBTURATOR FORMS A GAS-TIGHT SEAL BETWEEN THE CARTRIDGE AND GUN BORE AS A MISSILE IS PROJECTED FROM THE GUN. 